Circuit Description
When you first turn ON the ignition, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM proceeds with the resistance measurement test. During one portion of the resistance measurement test, the SDM does the following:
| • | Grounds the driver frontal low terminal through an internal current sink. |
| • | Connects the driver frontal high terminal to an internal constant current source. This current produces proportional voltage drops in the deployment loop. |
| • | Measures the voltage difference between driver frontal high and low circuits. |
| • | Calculates the resistance of the driver frontal deployment loop using the measured voltage. |
Conditions for Running the DTC
| • | Ignition 1 voltage is within the normal operating voltage range. |
| • | Driver frontal deployment loop is not open. |
| • | Driver frontal deployment loop is not shorted to voltage. |
| • | Driver frontal deployment loop is not shorted to ground. |
Conditions for Setting the DTC
Driver frontal deployment loop resistance is less than 1.7 ohms for 500 milliseconds.
Action Taken When the DTC Sets
The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.
Conditions for Clearing the DTC
| • | The resistance of the driver frontal deployment loop is greater than or equal to 1.7 ohms for 500 milliseconds. |
| • | You can issue a CLEAR CODES command |
| • | A history DTC will clear once 250 malfunction free ignition cycles have occurred |
When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.
Diagnostic Aids
The following can cause an intermittent condition:
| • | A short between the driver frontal high and the driver frontal low circuits. |
| • | A malfunctioning shorting bar on the inflatable restraint steering wheel module connector. |
| • | A malfunctioning shorting bar on the inflatable restraint steering wheel module coil steering column connector. |
If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This step checks the in-line connector below the steering wheel restraint module coil.
-
This step test for the proper operation of inflatable restraint steering wheel module coil and/or inflatable restraint steering wheel inflator module.
-
This step determines if there is a short between driver frontal high and driver frontal low circuits, or if there is a malfunctioning SDM.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | ||||||||
Does connector exhibits any signs of corrosion, terminal damaged, or poor connections? | -- | |||||||||
3 |
Did you complete the replacement? | -- | -- | |||||||
4 |
Does the scan tool indicate that this DTC is current? | -- | Go to Diagnostic Aids | |||||||
5 |
Does the scan tool indicate that this DTC is current? | -- | ||||||||
Does the scan tool indicate that this DTC is current? | -- | |||||||||
7 |
Did you complete the replacement? | -- | -- | |||||||
8 |
Did you complete the replacement? | -- | -- | |||||||
Does the resistance measure less than the specified value? | OL | |||||||||
10 | Locate and repair a short between the driver frontal high and the driver frontal low deployment circuits of the SDM harness connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
11 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | -- | |||||||
12 |
Did you complete the action? | -- | -- |
